oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 714 )

2018 ( 987 )

2017 ( 919 )

2016 ( 1353 )

Custom range...

Search Results: 1 - 10 of 553918 matches for " B. A. Shainyan "
All listed articles are free for downloading (OA Articles)
Page 1 /553918
Display every page Item
Novel Technology for Chlorination of Niobium and Tantalum Oxides and Their Low-Grade Ore Concentrates  [PDF]
B. A. Shainyan, Yu. S. Danilevich, Yu. L. Garmazov, A. L. Finkelstein, T. S. Aisueva, V. K. Turchaninov
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2008, DOI: 10.4236/jmmce.2008.72013
Abstract: A novel energy-economic and environmentally benign technological procedure for chlorination of niobium and tantalum oxides as well as their low-grade ore concentrates was elaborated. The process is based on using carbon tetrachloride or silicon tetrachloride as a chlorinating agent under pressure. It proceeds at moderate temperatures and is free from the shortcomings of conventional carbochlorination processes such as the use of chlorine gas at very high temperatures and formation of toxic products and ozone depleting agents (phosgene, carbon monoxide, chlorohydrocarbons).
Effect of Mechanical and Chemical Scarification on Germination of Dodder (Cuscuta campestris Yunck.) Seed  [PDF]
A. B. Mustapha, N. A. Gworgwor, B. B. Jakusko
World Journal of Engineering and Technology (WJET) , 2015, DOI: 10.4236/wjet.2015.33B006
Abstract:

Experiments were carried out to evaluate the effect of seed treatment on germination of Cuscuta campestris. This may provide the possible ways to overcome the problem of dormancy in Cuscuta campestris. The experiments were conducted in the Laboratory of Crop Production and Horticulture, Modibbo Adama University of Technology, Yola, Adamawa State, Nigeria, using mechanical scarification and tetraoxosulphate (VI) acid (H2SO4). For the mechanical scarification the treatments were unscarified, scarified using sandpaper and scarified using gravel arranged in a completely randomized design (CRD) and replicated four times. For the tetraoxosulphate (VI) acid (H2SO4) scarification, the treatment of control, 9:1, 7:3, 1:1, 4:6, 3:7, 2:8 and 1:9 H2SO4 were laid out in a Split plot design and replicated three times. The mechanical scarification was not significant (P ≤ 0.05), a rapid increase of germination from day 3 to day 9 was observed, and the highest rate of germination percentage (14% - 22%) obtained on day 9. Tetraoxosulphate (VI) acid treatment of 4:6 concentrations significantly gave the highest C. campestris seeds germination percentage (40.07%) compared with the rest of the treatments, while the time of soaking the seeds in the tetraoxosulphate (VI) acid showed that soaking the seeds for 1 minute significantly gave the highest percentage germination (39.98%) of C. campestris compared with the 3 and 5 minutes soaking treatments. It can be concluded that sulphuric acid of 4:6 concentrations treatments has the potentiality to break dormancy of C. campestris seeds.

Knowledge and Practice of Fundoscopy among Medical Doctors in Port Harcourt, Nigeria  [PDF]
A. A. Onua, B. Fiebai
Open Journal of Ophthalmology (OJOph) , 2016, DOI: 10.4236/ojoph.2016.63023
Abstract: Background: Many clinical entities manifest early characteristic changes in the fundus of the eye. The value of fundoscopy cannot be overemphasized and every medical doctor is expected to be able to use the ophthalmoscope to detect common pathological changes. However, more often than not fundoscopy is seen as an exclusive specialized skill of the ophthalmologist. Aim: The aim of this study was to evaluate knowledge and practice of fundoscopy among the physicians present at the Ordinary General Meeting of the Nigerian Medical Association (Rivers State branch) held in Port Harcourt on 30th June 2014. Methods: A self administered questionnaire about their knowledge and practice of fundoscopy was administered to 125 medical doctors attending the Ordinary General Meeting of the Nigerian Medical Association (Rivers State branch) held in Port Harcourt on 30th June 2014. Questions asked tested the Knowledge and Practice of the physicians on matters related to fundoscopy. Participants’ knowledge and practice were graded as Good for scores of 75% and above, Fair for 50% - 74% score and Poor for scores less than 50%. Respondents’ demographic data, responses and corresponding scores were entered into computer software—Scientific Package for Social Sciences (SPSS) version 20 and subsequently analyzed. Results: The study participants were 125 physicians; 86 males and 39 females (M:F = 2.2:1). Twenty-eight percent of the study participants had good knowledge of fundoscopy while only 15% had good practice. Seventy eight physicians representing 62.4% of the participants could correctly refer patients with the need for fundoscopy to an ophthalmologist, whereas 11 (8.8%) worked in facilities without basic instrument for fundoscopy (ophthalmoscope). Conclusion: Our study demonstrates that knowledge and practice of fundoscopy among medical practitioners in Port Harcourt is poor and far from ideal. Therefore, refresher courses emphasizing the acquisition of the skill in fundoscopy and the provision of ophthalmoscopes in our General Practitioners’ clinics are necessary.
Prevalence, Causes and Management of Neovascular Glaucoma: A 5-Year Review  [PDF]
B. Fiebai, A. A. Onua
Open Journal of Ophthalmology (OJOph) , 2019, DOI: 10.4236/ojoph.2019.91001
Abstract: Purpose: To determine the prevalence, identify the causes and outline the management options available at our center for the treatment of neovascular glaucoma. Setting: The study was carried out in the department of ophthalmology, University of Port Harcourt Teaching Hospital, Port Harcourt, Rivers State, Nigeria. Methods: The case records of all patients who were managed in the department of ophthalmology from January 2013 to December 2017 for neovascular glaucoma were retrieved. Data collected included, age, sex, causes of neovascular glaucoma, presenting visual acuity, treatment options and outcomes, systemic and ocular comorbidities. Results were analysed using Statistical Package for Social Sciences (SPSS) 20.0 for Windows statistical software. Results: Thirty-two eyes (32) of twenty-eight patients were studied. The hospital prevalence of neovascular glaucoma was 0.3%. There were 4 cases of bilateral neovascular glaucoma (NVG). Retinal vein occlusion 17 (53%) was the commonest cause of NVG followed by proliferative diabetic retinopathy 13 (41%). Uveitis was seen in only 2 (6%) eyes. The commonest form of intervention used was a combination of medical therapy and anti VEGFs. Fifty percent (50%) of the study population had a lowering of their intraocular pressures within the normal limits post treatment and this was statistically significant (p = 0.000). However, only 10% had an improvement in their visual acuity after treatment. Conclusions: Neovascular glaucoma is a potential blinding condition with challenges in control of intraocular pressures and preservation of vision. Early detection and attention to aetiological factors with timely institution of the appropriate mode of treatment may help in preserving vision.
Total Harmonic Distortion Minimization of Multilevel Converters Using Genetic Algorithms  [PDF]
A. Salami, B. Bayat
Applied Mathematics (AM) , 2013, DOI: 10.4236/am.2013.47139
Abstract:

This paper presents a genetic algorithm (GA) optimization technique to find the optimum switching angles of 11-level inverter with minimum number of dc sources and switches in comparison with the cascade multilevel inverter in order to minimize the total harmonic distortion (THD) of their output voltage waveform. Theoretical and simulation results for an 11-level converter show the efficiency of the proposed algorithm to determine the optimum angles in order to decrease the undesired harmonics and produce very high quality output voltage waveform.

Confrontation between Quantized Periods of Some Extra-Solar Planetary Systems and Observations  [PDF]
A. B. Morcos
International Journal of Astronomy and Astrophysics (IJAA) , 2013, DOI: 10.4236/ijaa.2013.32A005
Abstract:

A simple formula, using the quantum numbers of solar system planets and some quantized extra-solar planets, to estimate the periods, is done. The quantum numbers, calculated by other authors, have been used to find the orbital periods of solar system planets and some extra-solar planets. Observed periods have been used to compare them with the estimated periods from the given formula. It is found that the given relation is applicable perfectly for the solar system planets. Some extra-solar planets, of stars having approximately the same mass as the sun, are chosen to apply the same relation. The differences between the observed and calculated periods for the extra-solar systems have been calculated and tabulated. It is found that the percentage errors between the predicted values and the corresponding observed values for extra-planetary systems are controlled by the star’s mass and its quantum number. The percentage error decreases by increasing the quantum number, for quantum numbers over 4. When the quantum number is less than or equal 4, it is found that the percentage error decreases by decreasing the quantum number.

Sums of Squares of Fibonacci Numbers with Prime Indices  [PDF]
A. Gnanam, B. Anitha
Journal of Applied Mathematics and Physics (JAMP) , 2015, DOI: 10.4236/jamp.2015.312186
Abstract: In this paper we present some identities for the sums of squares of Fibonacci and Lucas numbers with consecutive primes, using maximal prime gap G(x)~log2x, as indices.
Sums of Squares of Polygonal Numbers  [PDF]
A. Gnanam, B. Anitha
Advances in Pure Mathematics (APM) , 2016, DOI: 10.4236/apm.2016.64019
Abstract: Polygonal numbers and sums of squares of primes are distinct fields of number theory. Here we consider sums of squares of consecutive (of order and rank) polygonal numbers. We try to express sums of squares of polygonal numbers of consecutive orders in matrix form. We also try to find the solution of a Diophantine equation \"\"in terms of polygonal numbers.
Fuzzy Based BEENISH Protocol for Wireless Sensor Network  [PDF]
A. Devasena, B. Sowmya
Circuits and Systems (CS) , 2016, DOI: 10.4236/cs.2016.78164
Abstract: The main parameter to be considered in the wireless sensor network is the amount of energy that is available in each sensor node. The lifetime of the sensor node (SN) depends on it. As the SNs are deployed in remote locations, if the entire energy is consumed, it would be very difficult to replace or recharge the energy source immediately. Hence the energy consumed by each node is very important. If individual SNs send information directly to the base station (BS), then the availability of energy in such SN decreases very fast. This will lead to reduction in the life time of the SN. Instead, the SNs can send the data to the cluster head (CH), then the CH consolidates the received data. The CH sends it to the BS periodically. In this way, utilizing CH for sending the information to the BS increases the lifetime of the SN. The cluster head selection is very crucial in such networks. This paper proposes a novel fuzzy based BEENSIH protocol for CH selection.
Implementation of an Efficient Light Weight Security Algorithm for Energy-Constrained Wireless Sensor Nodes  [PDF]
A. Saravanaselvan, B. Paramasivan
Circuits and Systems (CS) , 2016, DOI: 10.4236/cs.2016.79194
Abstract: In-network data aggregation is severely affected due to information in transmits attack. This is an important problem since wireless sensor networks (WSN) are highly vulnerable to node compromises due to this attack. As a result, large error in the aggregate computed at the base station due to false sub aggregate values contributed by compromised nodes. When falsified event messages forwarded through intermediate nodes lead to wastage of their limited energy too. Since wireless sensor nodes are battery operated, it has low computational power and energy. In view of this, the algorithms designed for wireless sensor nodes should be such that, they extend the lifetime, use less computation and enhance security so as to enhance the network life time. This article presents Vernam Cipher cryptographic technique based data compression algorithm using huff man source coding scheme in order to enhance security and lifetime of the energy constrained wireless sensor nodes. In addition, this scheme is evaluated by using different processor based sensor node implementations and the results are compared against to other existing schemes. In particular, we present a secure light weight algorithm for the wireless sensor nodes which are consuming less energy for its operation. Using this, the entropy improvement is achieved to a greater extend.
Page 1 /553918
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.